John Bald is a former Ofsted inspector who has written two books on the teaching of reading and spelling.

The education select committee’s rejection of Nicky Morgan’s preferred candidate for the post of Chief Inspector is the most important decision in its history, and came as a shock. The tone of the pre-appointment hearing was low-key and cordial, with only the hint of what was in the balance from Neil Carmichael’s opening remark that the committee was to assess Amanda Spielman’s suitability for the post.

Surely the Secretary of State, following Crown Appointments procedures to the letter, could not nominate someone who was unsuitable. Ms Spielman had done well at ARK schools and Ofqual, has excellent analytic skills and has a quiet, reasonable approach that would be a pleasant contrast from some of the “blunt speaking” (to quote Sir Michael Wilshaw) that we have had from chief inspectors. Ms Spielman was even endorsed in The Guardian by Laura McInerney.

Nicky Morgan has asked the committee to reconsider, and it held a private meeting on Tuesday before publishing its report. Unlike US congressional committees, the select committee has no veto on the appointment, and is now in an unprecedented public standoff with the Secretary of State, with the most unfortunate Ms Spielman in the middle. As I write, there is no sign that anyone will back down, but it would place a new chief inspector in a most difficult position if he or she were appointed in the teeth of such a negative report. We should not expect the present situation to last long.

The committee’s target, however, is not the present candidate, but the changes made to Ofsted by Labour in 2005-6, which put it in charge of virtually everything connected with children, and particularly social work, in line with Blair’s idea of joined-up government. A Labour place-man, David Bell, who had attended Blair’s victory party in 1997, was brought in to replace the highly competent Sir Michael Tomlinson, and Her Majesty’s Inspectors of Schools, who were themselves a watchword for competence among their inspector colleagues in other countries, were turned, with a few honourable exceptions, into government agents.

The vast new role was financed by slashing school inspections beyond the bone, so that they were no longer based on first hand evidence, but on highly questionable data, with inspections controlled by Ofsted and not the lead inspector.

I did not believe at the time that David Bell or anyone else had the skills needed to manage social services as well as education, and Ofsted walked straight into a scandal with a murder in Haringey that had been preceded by a botched inspection. A second report, by an expert HMI, showed up the problems, but could not address the structural defects in Ofsted itself.

The light touch inspection, based on reading the school’s database and a quick walk round the school – if that – did not detect the Trojan Horse scandals in Birmingham and led to the widespread fear and injustice that I described last week. Sir Michael, in setting out to do God’s work, had turned the organisation into something uncomfortably close to the holy inquisition – the head who had told me she was terrified of it was leading a very successful church school.

The committee has repeated the call of its predecessor for a separate inspectorate of children’s services, and this must be heeded. As a specialist in learning difficulties, and inspector of special schools, I worked more closely with children’s social services than most people in education, and I knew perfectly well that I would not have been competent to do their work, let alone inspect it. The issues in residential care alone, with the constant risks of serious crime and abuse, require specialist knowledge and understanding of the highest level.

The committee states bluntly that it does not consider that Ofsted’s senior management have the experience they need to do the work properly, and this must be heeded.

David Cameron’s first government began to return education to its proper purposes by getting rid of Labour’s “Children Schools and Families” department. Ofsted was set up in the image of this monstrosity, and has failed. The committee’s judgement is correct. Its report must be read carefully, and must lead to action.